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U Sagittarii

HR 6947, BSC 6947

Yellow supergiant in Sagittarius

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Proper Name	None
Bayer Designation	None
Flamsteed Number	None
HR (BSC)	6947
HD	170764
Variable Designation	U Sagittarii
Constellation	Sagittarius
Right Ascension	18h 31m 53s
Declination	-19° 7' 30"
Distance	c. 2,100 light years c. 600 parsecs
Magnitude	Apparent: +6.38 Absolute: -2.64
Spectral Class	G1.5Ib yellow supergiant
Optimum Visibility	July

The supergiant U Sagittarii is the brightest member of the open cluster M25, whose stars can be see here spreading to the south and west of yellow-orange U Sagittarii itself. Imagery provided by Aladin sky atlas

This vast and highly luminous star lies in the heart of the open star cluster designated M25. It is a Cepheid variable, meaning that it periodically swells and contracts. The pattern of this variability allows us to calculate its distance from the Earth, giving a value of more than two thousand light years.

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